Assume long serving politicians are rationally maximizing their careers

This is not the only story about Bill Clinton's charisma that's out. I looked into the subject deeper in the past. It's the thing I could easily find on Google. 

supposedlyfun's comment about how his grandmother has a similar experience shows that this isn't just one isolated episode.

I don't find it plausible that the explanation of Bill Clinton's charisma is just about eye contact. Many people manage to hold good eye contact but don't reach the same results.

My point is not that charisma generally helps but that you have leader at the top who are good at one very specific thing. 

For Obama for example it's not 1-on-1 charisma but his ability to give speeches in a way that makes people feel things. 

I don't understand Trump to the level of being able to point at the one thing that Trump was really good at, but Trump is also an example of someone who seemed to be good at specific things that allowed him to dominate the media and that allowed him to be extremely bad at others. 

Essentially, some people have "superpowers" and 3/5 of the last US presidents had one. If you count being the son of another president and the connections that come with that as an additional superpower it's 4/5. I'm unsure about Biden, but I have relatively little information about Biden that's goes deeper then political spin.

Many political candiates have nothing expectional going for them and when you see the people becoming president having superpowers, it might not be because they are any better at making political decisions then the average political candiates.

If making smart decisions was mainly about what gets you to be president we would see that US presidents that are as smart as FED chairmens but I don't believe that any of the last five US presidents have an IQ of more then 140 (with the possible expectation of Bush where someone working with him made claims that Bush was that smart and Michael Moore more making a comment of how Bush being mentally quick enough to outwit him suggests that Bush is very smart). 

GJM’s interpretation is my intended meaning. Specifically I meant Pelosi’s intransigence, Boris’s strategic position changes and fake awkwardness. For khameini I was referencing the nuclear bullshit which is destroying Iran’s economy and obviously a bad deal, but good for his career. As evidence it’s a bad deal, observe that only 1 other country trolls the big five with nukes. But all of this allowed Nancy to stay speaker for years, Boris to go from mayor of London to PM and khameini to rule for 30 years

It's worthwhile that this mechanism makes it easy to understand why North Korea has it's military first-policy. There are no powerful businessman and even when it means that people starve being popular with the military is what's necessary to keep political power. 

Yes! That’s exactly what I was suggesting! Couldn’t have put it better myself.